In order to find out the effects of the amount of deposited fat on the pork quality, the factors affecting the PSE porcine muscle were investigated. The results are summarized as follows; 1. Of 10,993 experimental swine, 4,225 individuals (38.6%) had PSE porcine muscle. 2. Severe stress by the high temperature which the pigs were exposed to before slaughter became a direct cause of the occurence of the PSE porcine muscle. 3. The PSE porcine muscle occured more often in the heavy carcass weight and in the male. 4. The incidence of the PSE porcine muscle were higher in swine which had a thick backfat. 5. The incidence of the PSE porcine muscle showed almost no correlation with the loin-eye area. 6. The price of carcass at whole sale market was determined according to backfat thickness and intramuscular fat.